When a display device performs displaying, it needs to utilize a shift register to realize scanning of a pixel unit. The shift register comprises a plurality of shift register units, each of which is corresponding to one row of pixel units and provides a gate drive signal for the pixel units. In this way, progressive scanning and driving of the pixel units of the display device is realized by the plurality of shift register units, so as to display an image.
However, an input module in the shift register unit comprises transistors. The transistors have threshold voltages, and the threshold voltages of the transistors of the input modules in the respective shift register units manufactured in the manufacturing process are often different. There occurs easily to transistors whose threshold voltages drift forwards under the effect of a trigger signal a phenomenon of being not fully turned on. The influence of the threshold voltage causes that time lengths that transistors of subsequent circuits in the respective shift register units are turned on fully are different. Therefore, duration length of a rising edge or a falling edge of a gate drive signal output by the respective shift register units is different, thereby causing a non-uniform display of the display device. In the scenario that the threshold voltage drifts forwards very severely, the transistors of the subsequent circuits cannot even be turned on, so that display effect of the display device is reduced.